please add a menu item: open terminal

[devvythelopper]

NERDTree allows you to run a system command, but neovim (don't know about others) has the ability to open terminal windows. It would be great if the default menu allowed me to just open such a terminal window from a point in the tree, so that the working directory then is the one in the tree. If I am on a file, maybe that file could be placed in a NERD_TREE_FIELE environment variable inside that terminal if possible.